Repository /TunedIT/core.jar:org.tunedit.core.ResourceLoader

/*
 *  Copyright (C) 2009 by TunedIT. All rights reserved.
 *
 */
package org.tunedit.core;

import java.io.IOException;
import java.io.InputStream;
import java.security.PrivilegedActionException;
import java.util.List;

import org.tunedit.core.exception.TunedTesterException;

/**
 * Loader of resources from TunedIT Repository.
 * Used by {@link #EvaluationProcedure EvaluationProcedures} to load the resources needed
 * to set up a test.
 * Typically, evaluation procedure does not use ResourceLoader directly,
 * but instead constructs an instance of {@link #StandardLoader}
 * which encapsulates the original ResourceLoader and extends it
 * with more convenient methods for accessing resources.
 * In such case, original ResourceLoader is used only to create a StandardLoader.
 * 
 * @author Marcin Wojnarski
 *
 */
public interface ResourceLoader {

	/**
	 * Downloads the resource from TunedIT Repository, saves it as a file on local disk 
	 * (in TunedTester cache folder), opens it for reading
	 * and returns a <code>java.io.InputStream</code> that can be used by client
	 * to read the contents of the file.
	 * <code>InputStream</code> enables low-level byte-wise access to data.
	 * If you need more high-level access, e.g. you expect a text file not a binary,
	 * you can easily convert this byte stream into character stream
	 * with <code>java.io.InputStreamReader</code> class.
	 * 
	 * @param fileResource  TunedIT resource name of the requested resource.
	 * Must represent a file resource.
	 * @return InputStream for reading the contents of the resource.
	 */
	public abstract InputStream open(ResourceName fileResource) throws TunedTesterException;


	/**
	 * Downloads the resource from TunedIT Repository, saves it as a file on local disk 
	 * (in TunedTester cache folder), runs it as an external process
	 * and returns a wrapper class providing a convenient interface 
	 * 
	 * @param fileResource  TunedIT resource name of the requested resource.
	 * Must represent a file resource.
	 * @return String Path to the downloaded file
	 * @throws IOException 
	 * @throws PrivilegedActionException 
	 */
	public abstract ExternalProcess runProcess(ResourceName fileResource, List<String> args) throws TunedTesterException;
	
}